DiscreteNucleationInserter

Manages the list of currently active nucleation sites and adds new sites according to a given probability function.

The inserter manages the global list of currently active nucleus stabilization sites. This user object takes two parameters

hold_time - the duration in time for which a stabilization site remains active
probability - a material property containing a nucleation rate density. This material property can be calculated using classical nucleation theory for example.

The inserter object keeps track if any changes to the nucleus list occurred in the current timestep.

The DiscreteNucleationInserter is part of the Discrete Nucleation system.

Input Parameters

hold_timeTime to keep each nucleus active
C++ Type:double
Options:
Description:Time to keep each nucleus active
probabilityProbability density for inserting a discrete nucleus
C++ Type:MaterialPropertyName
Options:
Description:Probability density for inserting a discrete nucleus

Required Parameters

blockThe list of block ids (SubdomainID) that this object will be applied
C++ Type:std::vector
Options:
Description:The list of block ids (SubdomainID) that this object will be applied
execute_onTIMESTEP_ENDThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.
Default:TIMESTEP_END
C++ Type:ExecFlagEnum
Options:NONE INITIAL LINEAR NONLINEAR TIMESTEP_END TIMESTEP_BEGIN FINAL CUSTOM
Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.

Optional Parameters

allow_duplicate_execution_on_initialFalseIn the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).
Default:False
C++ Type:bool
Options:
Description:In the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).
control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector
Options:
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Options:
Description:Set the enabled status of the MooseObject.
implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Options:
Description:Determines whether this object is calculated using an implicit or explicit form
seed0The seed for the master random number generator
Default:0
C++ Type:unsigned int
Options:
Description:The seed for the master random number generator
use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
Default:False
C++ Type:bool
Options:
Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Advanced Parameters

Input Files

modules/phase_field/test/tests/Nucleation/auxkernel.i
modules/phase_field/test/tests/Nucleation/material.i
modules/phase_field/test/tests/Nucleation/parallel.i
modules/phase_field/examples/nucleation/refine.i
modules/phase_field/test/tests/Nucleation/timestep.i
modules/phase_field/test/tests/Nucleation/force.i
modules/phase_field/test/tests/Nucleation/marker.i
modules/phase_field/test/tests/Nucleation/data.i
modules/phase_field/examples/nucleation/cahn_hilliard.i

modules/phase_field/test/tests/Nucleation/auxkernel.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 20
  ny = 20
  nz = 0
  xmin = 0
  xmax = 20
  ymin = 0
  ymax = 20
  elem_type = QUAD4
[]

[AuxVariables]
  [./c]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[AuxKernels]
  [./c]
    type = DiscreteNucleationAux
    map = map
    variable = c
    no_nucleus_value = -1
    nucleus_value = 2
    execute_on = TIMESTEP_END
  [../]
[]

[UserObjects]
  [./inserter]
    type = DiscreteNucleationInserter
    hold_time = 0.4
    probability = 0.01
    seed = 12346
  [../]
  [./map]
    type = DiscreteNucleationMap
    radius = 3.27
    int_width = 2
    periodic = c
    inserter = inserter
  [../]
[]

[Executioner]
  type = Transient
  solve_type = 'NEWTON'
  num_steps = 10
  dt = 0.2
[]

[Problem]
  solve = false
  kernel_coverage_check = false
[]

[Outputs]
  execute_on = 'timestep_end'
  exodus = true
[]

modules/phase_field/test/tests/Nucleation/material.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  nz = 0
  xmin = 0
  xmax = 20
  ymin = 0
  ymax = 20
[]

[Variables]
  [./c]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[BCs]
  [./left]
    type = DirichletBC
    boundary = left
    variable = c
    value = 0
  [../]
  [./right]
    type = DirichletBC
    boundary = right
    variable = c
    value = 1
  [../]
  [./Periodic]
    [./all]
      auto_direction = y
    [../]
  [../]
[]

[Kernels]
  [./c]
    type = Diffusion
    variable = c
  [../]
  [./dt]
    type = TimeDerivative
    variable = c
  [../]
[]

[Materials]
  [./nucleation]
    type = DiscreteNucleation
    op_names  = c
    op_values = 1
    map = map
    outputs = exodus
  [../]
[]

[UserObjects]
  [./inserter]
    type = DiscreteNucleationInserter
    hold_time = 1
    probability = 0.01
  [../]
  [./map]
    type = DiscreteNucleationMap
    radius = 3.27
    periodic = c
    inserter = inserter
  [../]
[]

[Executioner]
  type = Transient
  solve_type = 'NEWTON'
  num_steps = 10
  dt = 0.1
[]

[Outputs]
  execute_on = 'timestep_end'
  exodus = true
  hide = c
[]

modules/phase_field/test/tests/Nucleation/parallel.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 100
  ny = 100
  nz = 0
  xmin = 0
  xmax = 20
  ymin = 0
  ymax = 20
[]

[GlobalParams]
  derivative_order = 2
[]

[Variables]
  [./c]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[BCs]
  [./Periodic]
    [./all]
      auto_direction = 'x y'
    [../]
  [../]
[]

[Kernels]
  [./c]
    type = Diffusion
    variable = c
  [../]
  [./dt]
    type = TimeDerivative
    variable = c
  [../]
[]

[Materials]
  [./nucleation]
    type = DiscreteNucleation
    op_names  = c
    op_values = 1
    map = map
  [../]
[]

[UserObjects]
  [./inserter]
    type = DiscreteNucleationInserter
    hold_time = 1
    probability = 0.01
  [../]
  [./map]
    type = DiscreteNucleationMap
    radius = 4
    periodic = c
    inserter = inserter
  [../]
[]

[Postprocessors]
  [./sum]
    type = ElementIntegralMaterialProperty
    mat_prop = F
  [../]
[]

[Executioner]
  type = Transient
  solve_type = 'NEWTON'
  num_steps = 10
  dt = 0.1
[]

[Outputs]
  execute_on = 'timestep_end'
  [./out]
    type = CSV
  [../]
[]

modules/phase_field/examples/nucleation/refine.i

#
# Example derived from cahn_hilliard.i demonstrating the use of Adaptivity
# with the DiscreteNucleation system. The DiscreteNucleationMarker triggers
# mesh refinement for the nucleus geometry. It is up to the user to specify
# refinement for the physics. In this example this is done using a GradientJumpIndicator
# with a ValueThresholdMarker. The nucleation system marker and the physics marker
# must be combined using a ComboMarker to combine their effect.
#

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  xmax = 500
  ymax = 500
  elem_type = QUAD
[]

[Modules]
  [./PhaseField]
    [./Conserved]
      [./c]
        free_energy = F
        mobility = M
        kappa = kappa_c
        solve_type = REVERSE_SPLIT
      [../]
    [../]
  [../]
[]

[ICs]
  [./c_IC]
    type = ConstantIC
    variable = c
    value = 0.2
  [../]
[]

[Materials]
  [./pfmobility]
    type = GenericConstantMaterial
    prop_names  = 'M kappa_c'
    prop_values = '1 25'
  [../]
  [./chemical_free_energy]
    # simple double well free energy
    type = DerivativeParsedMaterial
    f_name = Fc
    args = 'c'
    constant_names       = 'barr_height  cv_eq'
    constant_expressions = '0.1          0'
    function = 16*barr_height*c^2*(1-c)^2 # +0.01*(c*plog(c,0.005)+(1-c)*plog(1-c,0.005))
    derivative_order = 2
    outputs = exodus
  [../]
  [./probability]
    # This is a made up toy nucleation rate it should be replaced by
    # classical nucleation theory in a real simulation.
    type = ParsedMaterial
    f_name = P
    args = c
    function = 'if(c<0.21,c*1e-8,0)'
    outputs = exodus
  [../]
  [./nucleation]
    # The nucleation material is configured to insert nuclei into the free energy
    # tht force the concentration to go to 0.95, and holds this enforcement for 500
    # time units.
    type = DiscreteNucleation
    f_name = Fn
    op_names  = c
    op_values = 0.90
    penalty = 5
    penalty_mode = MIN
    map = map
    outputs = exodus
  [../]
  [./free_energy]
    # add the chemical and nucleation free energy contributions together
    type = DerivativeSumMaterial
    derivative_order = 2
    args = c
    sum_materials = 'Fc Fn'
  [../]
[]

[UserObjects]
  [./inserter]
    # The inserter runs at the end of each time step to add nucleation events
    # that happend during the timestep (if it converged) to the list of nuclei
    type = DiscreteNucleationInserter
    hold_time = 50
    probability = P
  [../]
  [./map]
    # The map UO runs at the beginning of a timestep and generates a per-element/qp
    # map of nucleus locations. The map is only regenerated if the mesh changed or
    # the list of nuclei was modified.
    # The map converts the nucleation points into finite area objects with a given radius.
    type = DiscreteNucleationMap
    radius = 10
    periodic = c
    inserter = inserter
  [../]
[]

[Preconditioning]
  [./SMP]
    type = SMP
    full = true
  [../]
[]

[BCs]
  [./Periodic]
    [./all]
      auto_direction = 'x y'
    [../]
  [../]
[]

[Postprocessors]
  [./dt]
    type = TimestepSize
  [../]
  [./ndof]
    type = NumDOFs
  [../]
  [./rate]
    type = DiscreteNucleationData
    value = RATE
    inserter = inserter
  [../]
  [./dtnuc]
    type = DiscreteNucleationTimeStep
    inserter = inserter
    p2nucleus = 0.0005
    dt_max = 10
  [../]
  [./update]
    type = DiscreteNucleationData
    value = UPDATE
    inserter = inserter
  [../]
  [./count]
    type = DiscreteNucleationData
    value = COUNT
    inserter = inserter
  [../]
[]

[Adaptivity]
  [./Indicators]
    [./jump]
      type = GradientJumpIndicator
      variable = c
    [../]
  [../]
  [./Markers]
    [./nuc]
      type = DiscreteNucleationMarker
      map = map
    [../]
    [./grad]
      type = ValueThresholdMarker
      variable = jump
      coarsen = 0.1
      refine = 0.2
    [../]
    [./combo]
      type = ComboMarker
      markers = 'nuc grad'
    [../]
  [../]
  marker = combo
  cycles_per_step = 3
  recompute_markers_during_cycles = true
  max_h_level = 3
[]

[Executioner]
  type = Transient
  scheme = bdf2
  solve_type = 'PJFNK'
  petsc_options_iname = '-pc_type -sub_pc_type'
  petsc_options_value = 'asm      lu          '

  nl_max_its = 20
  l_tol = 1.0e-4
  nl_rel_tol = 1.0e-10
  nl_abs_tol = 1.0e-10
  start_time = 0.0
  num_steps = 120

  [./TimeStepper]
    type = IterationAdaptiveDT
    dt = 10
    growth_factor = 1.5
    cutback_factor = 0.5
    optimal_iterations = 8
    iteration_window = 2
    timestep_limiting_postprocessor = dtnuc
  [../]
[]

[Outputs]
  exodus = true
  csv = true
  print_linear_residuals = false
[]

modules/phase_field/test/tests/Nucleation/timestep.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 2
  ny = 2
  nz = 0
  xmin = 0
  xmax = 20
  ymin = 0
  ymax = 20
[]

[Variables]
  [./c]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[BCs]
  [./left]
    type = DirichletBC
    boundary = left
    variable = c
    value = 0
  [../]
  [./right]
    type = DirichletBC
    boundary = right
    variable = c
    value = 1
  [../]
  [./Periodic]
    [./all]
      auto_direction = y
    [../]
  [../]
[]

[Kernels]
  [./c]
    type = Diffusion
    variable = c
  [../]
  [./dt]
    type = TimeDerivative
    variable = c
  [../]
[]

[UserObjects]
  [./inserter]
    type = DiscreteNucleationInserter
    hold_time = 1
    probability = 0.0005
  [../]
  [./map]
    type = DiscreteNucleationMap
    radius = 3.27
    periodic = c
    inserter = inserter
  [../]
[]

[Postprocessors]
  [./dt]
    type = TimestepSize
  [../]
  [./dtnuc]
    type = DiscreteNucleationTimeStep
    inserter = inserter
    p2nucleus = 0.1
    dt_max = 0.5
  [../]
[]

[Executioner]
  type = Transient
  solve_type = 'NEWTON'
  num_steps = 20

  [./TimeStepper]
    type = IterationAdaptiveDT
    optimal_iterations = 8
    iteration_window = 2
    timestep_limiting_postprocessor = dtnuc
    dt = 1
  [../]
[]

[Outputs]
  execute_on = 'timestep_end'
  csv = true
[]

modules/phase_field/test/tests/Nucleation/force.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 20
  ny = 20
  nz = 0
  xmin = 0
  xmax = 20
  ymin = 0
  ymax = 20
  elem_type = QUAD4
[]

[Variables]
  [./c]
  [../]
[]

[Kernels]
  [./c_force]
    type = DiscreteNucleationForce
    variable = c
    map = map
    no_nucleus_value = -1
    nucleus_value = 2
  [../]
  [./c_react]
    type = Reaction
    variable = c
  [../]
[]

[UserObjects]
  [./inserter]
    type = DiscreteNucleationInserter
    hold_time = 0.4
    probability = 0.01
    seed = 12346
  [../]
  [./map]
    type = DiscreteNucleationMap
    radius = 3.27
    int_width = 2
    periodic = c
    inserter = inserter
  [../]
[]

[Executioner]
  type = Transient
  solve_type = 'NEWTON'
  nl_abs_tol = 1e-10
  num_steps = 10
  dt = 0.2
[]

[Outputs]
  execute_on = 'timestep_end'
  exodus = true
[]

modules/phase_field/test/tests/Nucleation/marker.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 2
  ny = 2
  nz = 0
  xmin = 0
  xmax = 20
  ymin = 0
  ymax = 20
[]

[Variables]
  [./c]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[BCs]
  [./left]
    type = DirichletBC
    boundary = left
    variable = c
    value = 0
  [../]
  [./right]
    type = DirichletBC
    boundary = right
    variable = c
    value = 1
  [../]
  [./Periodic]
    [./all]
      auto_direction = y
    [../]
  [../]
[]

[Kernels]
  [./c]
    type = Diffusion
    variable = c
  [../]
  [./dt]
    type = TimeDerivative
    variable = c
  [../]
[]

[Materials]
  [./nucleation]
    type = DiscreteNucleation
    op_names  = c
    op_values = 1
    map = map
    outputs = exodus
  [../]
[]

[UserObjects]
  [./inserter]
    type = DiscreteNucleationInserter
    hold_time = 1
    probability = 0.01
  [../]
  [./map]
    type = DiscreteNucleationMap
    radius = 3.27
    periodic = c
    inserter = inserter
  [../]
[]

[Adaptivity]
  [./Markers]
    [./nuc]
      type = DiscreteNucleationMarker
      map = map
    [../]
  [../]
  marker = nuc
  cycles_per_step = 3
  recompute_markers_during_cycles = true
  max_h_level = 3
[]

[Executioner]
  type = Transient
  solve_type = 'NEWTON'
  num_steps = 10
  dt = 0.1
[]

[Outputs]
  execute_on = 'timestep_end'
  exodus = true
  hide = c
[]

modules/phase_field/test/tests/Nucleation/data.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 2
  ny = 2
  nz = 0
  xmin = 0
  xmax = 20
  ymin = 0
  ymax = 20
  elem_type = QUAD4
[]

[Variables]
  [./c]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[UserObjects]
  [./inserter]
    type = DiscreteNucleationInserter
    hold_time = 0.5
    probability = 0.0076
  [../]
[]

[Postprocessors]
  [./nuc_count]
    type = DiscreteNucleationData
    inserter = inserter
    value = COUNT
  [../]
  [./nuc_update]
    type = DiscreteNucleationData
    inserter = inserter
    value = UPDATE
  [../]
  [./nuc_rate]
    type = DiscreteNucleationData
    inserter = inserter
    value = RATE
  [../]
  [./nuc_insertions]
    type = DiscreteNucleationData
    inserter = inserter
    value = INSERTIONS
  [../]
  [./nuc_deletions]
    type = DiscreteNucleationData
    inserter = inserter
    value = DELETIONS
  [../]
[]

[Executioner]
  type = Transient
  num_steps = 10
  dt = 0.55
[]

[Problem]
  kernel_coverage_check = false
  solve = false
[]

[Outputs]
  execute_on = 'timestep_end'
  csv = true
[]

modules/phase_field/examples/nucleation/cahn_hilliard.i

#
# Test the DiscreteNucleation material in a toy system. The global
# concentration is above the solubility limit, but below the spinodal.
# Without further intervention no nucleation will occur in a phase
# field model. The DiscreteNucleation material will locally modify the
# free energy to coerce nuclei to grow.
#

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 120
  ny = 120
  xmax = 500
  ymax = 500
  elem_type = QUAD
[]

[Modules]
  [./PhaseField]
    [./Conserved]
      [./c]
        free_energy = F
        mobility = M
        kappa = kappa_c
        solve_type = REVERSE_SPLIT
      [../]
    [../]
  [../]
[]

[ICs]
  [./c_IC]
    type = RandomIC
    variable = c
    min = 0.2
    max = 0.21
  [../]
[]

[Materials]
  [./pfmobility]
    type = GenericConstantMaterial
    prop_names  = 'M kappa_c'
    prop_values = '1 25'
  [../]
  [./chemical_free_energy]
    # simple double well free energy
    type = DerivativeParsedMaterial
    f_name = Fc
    args = 'c'
    constant_names       = 'barr_height  cv_eq'
    constant_expressions = '0.1          0'
    function = 16*barr_height*c^2*(1-c)^2 # +0.01*(c*plog(c,0.005)+(1-c)*plog(1-c,0.005))
    derivative_order = 2
    outputs = exodus
  [../]
  [./probability]
    # This is a made up toy nucleation rate it should be replaced by
    # classical nucleation theory in a real simulation.
    type = ParsedMaterial
    f_name = P
    args = c
    function = c*1e-7
    outputs = exodus
  [../]
  [./nucleation]
    # The nucleation material is configured to insert nuclei into the free energy
    # tht force the concentration to go to 0.95, and holds this enforcement for 500
    # time units.
    type = DiscreteNucleation
    f_name = Fn
    op_names  = c
    op_values = 0.90
    penalty = 5
    penalty_mode = MIN
    map = map
    outputs = exodus
  [../]
  [./free_energy]
    # add the chemical and nucleation free energy contributions together
    type = DerivativeSumMaterial
    derivative_order = 2
    args = c
    sum_materials = 'Fc Fn'
  [../]
[]

[UserObjects]
  [./inserter]
    # The inserter runs at the end of each time step to add nucleation events
    # that happend during the timestep (if it converged) to the list of nuclei
    type = DiscreteNucleationInserter
    hold_time = 100
    probability = P
  [../]
  [./map]
    # The map UO runs at the beginning of a timestep and generates a per-element/qp
    # map of nucleus locations. The map is only regenerated if the mesh changed or
    # the list of nuclei was modified.
    # The map converts the nucleation points into finite area objects with a given radius.
    type = DiscreteNucleationMap
    radius = 10
    periodic = c
    inserter = inserter
  [../]
[]

[Preconditioning]
  [./SMP]
    type = SMP
    full = true
  [../]
[]

[BCs]
  [./Periodic]
    [./all]
      auto_direction = 'x y'
    [../]
  [../]
[]

[Postprocessors]
  [./dt]
    type = TimestepSize
  [../]
[]

[Executioner]
  type = Transient
  scheme = bdf2
  solve_type = 'PJFNK'
  petsc_options_iname = '-pc_type -sub_pc_type'
  petsc_options_value = 'asm      lu          '

  nl_max_its = 20
  l_tol = 1.0e-4
  nl_rel_tol = 1.0e-10
  nl_abs_tol = 1.0e-10
  start_time = 0.0
  num_steps = 1200

  [./TimeStepper]
    type = IterationAdaptiveDT
    dt = 10
    growth_factor = 1.5
    cutback_factor = 0.5
    optimal_iterations = 5
  [../]
[]

[Outputs]
  exodus = true
[]

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